Single Piece Rotating Spool for High-Pressure Lines

ABSTRACT

A rotating spool having elongated bolt holes or stadium bolt holes for rotating the spool for alignment of components attached to the ends.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX

Not Applicable.

BACKGROUND OF THE INVENTION Field of the Invention

The innovation generally relates to oil or gas wellbore equipment, and more particularly to connection of high-pressure fracturing equipment to wellbores.

Background of the Invention

Consumer demand for natural resources require companies to invest significant amounts of time and money in searching for and extracting oil, natural gas, and other subterranean resources from the earth. Once discovered, production and control of the resources to the maximum extraction is important.

Wellhead assemblies, including a wide variety of components, such as various castings, valves, fluid conduits, and the like are used to control drilling or extraction operations. Such assemblies may use a fracturing tree and other components to facilitate a fracturing process for enhancing production from a well. Fracturing processes facilitate extraction from fissures or cavities in various subterranean rock formations or strata.

Fracturing is the process of creating one or more man-made fractures in the target rock formations, which for example, may couple pre-existing fissures and cavities enhancing flow paths to the wellhead assembly. Fracturing processes include injecting a fracturing fluid, which includes grit/abrasives, into the wellhead at high pressures forcing it into the formation. Once pressure is released, the fissures remain open to fluid flow due to grit which remains trapped therein.

The fracturing process requires extensive equipment to produce the fluids and the high pressures. However, this equipment has limited service at a single location, and therefore must be adaptable to use on multiple wellheads. There is no standard to the construction of these target wellheads. Further, size and weight of the fracturing equipment means it is not simple to pick up and move one direction or another to facilitate alignments and connection with the wellhead.

Early solutions incorporated frac heads (also known as a goat head, flow cross, and by other names) to connect multiple lines of frac iron between the frac equipment and the wellhead. Recent improvements are the use of large-bore lines carrying the same fluid in less flow paths resulting in less equipment and less flow/pressure impedance. However, alignment issues increase due to the larger less maneuverable equipment.

Spools, comprised of relatively short lengths of pipe mounted between two flanges, have long existed as stand-ins for valves, meters, and other equipment added or removed from fluid lines. Such spools are often used in temporary installations such as frac processes to adjust lengths. But rotational alignment is still an issue.

U.S. Pat. No. 10,094,195 discussed a swivel spool composed of a fluid conduit with swivel connection (a swivel ring) at one end and a fixed, non-swivel connection (with a threaded flange) at the other end. Known as a Van Stone Flange, swivel flanges and threaded flanges can have leakage concerns are disfavored for high pressure application. Their use requires extra attention beyond that of normal assembly for this reason.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a typical swivel spool currently used in the O&G industry for rotational alignment of equipment.

FIG. 2 shows a single piece rotating spool for high-pressure lines in accordance with an exemplary embodiment of the innovation.

FIGS. 3A, 3B, & 3C show various projections of a counterclockwise embodiment of a single piece rotating spool for high-pressure lines in accordance with the innovation.

FIG. 4 illustrates an application of a single piece rotating spool for high pressure lines used to adjust the angle of a connection to a typical well bore frac tree in accordance with an exemplary embodiment of the innovation.

FIGS. 4A and 4B illustrate different alignment options possible by using clockwise or counterclockwise single piece rotating spools for high-pressure lines in accordance with exemplary embodiments of the innovation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The innovation described is a design for a single piece rotating spool for high-pressure lines having application in the Oil and Gas industry (O&G) for alignment of large-bore high-pressure lines such as the fluid conduits/pipes employed by fracturing processes. One skilled in the arts would appreciate applications in other pipe fitting environments.

The embodiment described, unless context dictates otherwise, is two flanges weld flanges joined by a short length of pipe providing at least clearance for hardware joining each flange to an adjacent element. The O&G industry generally uses American Petroleum Institute standards so in accordance with the default embodiment described herein the API 6A specification is assumed, but not required by the innovation. One skilled in the art will appreciate that the length, bore, schedule, bolt pattern, flange facing, etc. may vary in other embodiments.

A single piece spool does not have junctions within the spool that may leak. Normally a spool has bolt holes on each flange aligned across the spool or offset across the spool for a specific application. In the current innovation, bolt holes in each flange are elongated extending the circle into a stadium. However, elongation occurs radially so the stadium's major axis (extending between the vertices) is curved to match the Pitch Circle Diameter (PCD, a circle passing through the center of each bolt hole on the flange).

The opposite vertices of holes align on each flange, i.e. the hole's left vertex of one flange aligns with the right vertex of the other flange. Stated another way, aligning holes in each flange are elongated on each flange in opposite directions. This alignment may be to either direction producing spools with either a clockwise or a counterclockwise rotation from an aligned orientation.

Bolt patterns are specified by different standards maintained by different standards bodies and/or industries. But flanges compliant with the API 6A specification may have bolt holes of most large bore flanges elongated by at least four degrees (4°) without compromising the flange. Offset of the elongation in opposite directions allows the flange to rotate up to eight degrees (8°).

Different spools may be used to rotate components clockwise or counterclockwise. This means using either of the two spools accommodates alignment issues of up to sixteen degrees (16°). Since a twenty-four (24) bolt pattern commonly specified by API 6A has a fifteen degree (15°) offset between adjacent bolts, any alignment is possible prior to torqueing the retaining nuts, securing the line for flow of high-pressure fluids.

One skilled in the art will appreciate that other bolt patterns may have more than fifteen degrees (15°) of offset between bolts, but they may also tolerate more than four degrees (4°) of elongation without compromising the flange. Additionally, there is also the option of using multiple flanges with complementing rotation capabilities. Finally, it should be apparent to one skilled in the art that multiple spools oriented to different planes, such as by an elbow or connection block, can extend application to accommodating length issues by angular displacement from a straight line.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a typical swivel spool currently used in the O&G industry for rotational alignment of equipment. The pipe (110) includes a threaded surface (125) at one end and a stub end (133) at the distal end. When the pipe (110) is used as a swivel spool (100), the stub end (133) is received within the swivel ring (130).

This allows the stub end (133) (along with the pipe (110)) to rotate with respect to the swivel ring (130) and to the component to which the swivel ring (130) is attached (e.g., a connection block, fracturing manifold, or wellhead assembly). As depicted, the swivel ring (130) and the threaded flange (120) include through holes (150) to allow them to be connected to other components via studded connections.

The swivel connection at one end of a pipe (110) allows the pipe (110) to be rotated about its axis to change the orientation of the threaded flange (120) connection, which rotates with the pipe (110) at the end opposite the swivel. Through this rotation the fluid conduit can be changed to accommodate variances in rotational alignment.

FIG. 2 shows a single piece rotating spool for high-pressure lines in accordance with an exemplary embodiment of the innovation. The rotating spool (200) has flanges (220) affixed to each end of a length of pipe (210). The flanges (220) have bolt holes (250 & 260) elongated into stadiums that are curved along the PCD of the flange (220).

The opposite vertices of matching stadiums on each flange are aligned. This means viewing from one end, the right vertex of bolt holes (250) in the near flange align with the left vertex of bolt holes (260) in the far flange. In the counter version of the embodiment, viewing from one end, the left vertex of bolt holes (250) in the near flange align with the right vertex of bolt holes (260) in the far flange.

FIGS. 3A, 3B, & 3C show various projections of a counterclockwise embodiment of a single piece rotating spool for high-pressure lines in accordance with the innovation. FIG. 3A shows a front view of the spool. FIG. 3B shows a side cross section of the spool. FIG. 3C shows a middle cross section of the rear flange of the spool.

The rotating spool (200) has elongated bolt holes (250) in the front flange (220) and elongated bolt holes (260) in the rear flange (220). The left vertex of the front bolt holes (250) align with the right vertex of rear bolt holes (260). In the embodiment shown, the bolt pattern has 12 bolts and a thirty-degree (30°) bolt spacing. Ideally, the elongation of the bolt holes would be at least seven- and one-half degrees (7.5°), allowing full alignment options from a one spool.

FIG. 4 illustrates an application of a single piece rotating spool for high pressure lines used to adjust the angle of a connection to a typical well bore frac tree in accordance with an exemplary embodiment of the innovation. A rotating spool (200) mounted to a frac tree (300) can align a component between multiple positions (350 & 360).

FIGS. 4A and 4B illustrate different alignment options possible by using clockwise or counterclockwise single piece rotating spools for high-pressure lines in accordance with exemplary embodiments of the innovation. FIG. 4A shows a counterclockwise embodiment of a rotating spool (200) as indicated by the arrow at the bottom of the flange. FIG. 4B shows a clockwise embodiment of a rotating spool (200) as indicated by the arrow at the bottom of the flange.

FIG. 4A illustrates the ability to rotate a component from a first position (360) counterclockwise to a second position (350), after which bolts on the flanges can be tightened to secure the alignment. FIG. 4B illustrates the ability to rotate a component from a first position (360) clockwise to a second position (350), after which bolts on the flanges can be tightened to secure the alignment.

The diagrams in accordance with exemplary embodiments of the present innovation are provided as examples and should not be construed to limit other embodiments within the scope of the innovation. For instance, quantities, distances, and volumes may not be to scale and should not be construed to limit the innovation to the particular proportions. Additionally, some elements illustrated in the singularity may actually be implemented in a plurality, and those illustrated in the plurality could vary in actual count. Some elements illustrated in one form, design, or configuration may vary in detail from that depicted. Further, specific information should be interpreted as illustrative for discussing exemplary embodiments and is not provided to limit the innovation.

The above discussion is meant to be illustrative of the principles and various embodiments of the present innovation. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications. 

What is claimed is:
 1. An alignment spool comprising: a fluid conduit, a first flange attached to a first end, and a second flange attached to the distal end; the first and second flanges comprising: a central bore in fluid communication with the conduit, a plurality of bolt holes extending through the flange body circularly oriented around and having axis parallel to the central bore; each bolt hole of the first flange being elongated along the circumference of orientation.
 2. An alignment spool as described in claim 1 wherein: each bolt hole of the second flange is elongated along the circumference of orientation.
 3. An alignment spool as described in claim 2 wherein: the bolt holes of the first flange are elongated clockwise, and the bolt holes of the second flange are elongated counterclockwise.
 4. An alignment spool as described in claim 3 wherein: the left vertex of bolt holes of the first flange align with the right vertex of bolt holes of the second flange.
 5. An alignment spool as described in claim 2 wherein: the bolt holes of the first flange are elongated counterclockwise, and the bolt holes of the second flange are elongated clockwise.
 6. An alignment spool as described in claim 5 wherein: the right vertex of bolt holes of the first flange align with the left vertex of bolt holes of the second flange.
 7. An alignment spool as described in claim 1 wherein the fluid conduit further comprises a side port or valve.
 8. An alignment spool as described in claim 1 wherein the fluid conduit curves.
 9. An alignment spool as described in claim 2 wherein the fluid conduit further comprises a side port or valve.
 10. An alignment spool as described in claim 2 wherein the fluid conduit curves.
 11. An alignment spool as described in claim 10 wherein the first and second flanges are substantially perpendicularly oriented. 